The investigators aim to examine children and adolescents from 8 to 18 years suffering from diabetes mellitus type I for more than one year with an insulin requirement of more than 0.5 IU/kg/d. The investigators will exclude children with other chronic diseases, handicapped children or children suffering from cancer or chronic renal impairment, as well as children with other neurological diseases which can also cause a change in nerve conduction velocity, and children with blood glucose levels below 50 or above 350 mg/dl. At the time of the annual check-up the patients will undergo a detailed examination for anthropometric data, blood pressure, blood and urine. Thereafter, motor and sensory nerve conduction velocity will be determined by electrical stimulation using surface patch electrodes. The nerves to be investigated are the nervus tibialis anterior, nervus medianus and nervus peroneus. Finally, the patient will undergo a neurological investigation to calculate his Young Score (Neuropathy Symptom Score).